This page lists IPS patch files for RPG_RT.exe of RPG Maker 2000/2003 that change the width of all text rendered onto game-screen from 6 to 8 (wide characters and EXFONT are changed from 12 to 16, half-space from 3 to 4) pixels, while the height remains 12. To properly use this, you may have to replace the fonts used by the engine and insert a new EXFONT image into the EXE that features a width of 208 instead of 156 pixels.
This patch will not alter positions and size of texts in the engine's default menu-screens (this also includes F9 debugging), these will likely break-up a lot. TextWidthEight is primarily meant for games that don't use default menus but still utilize the default message-text display.
Be sure to pick a file that is for your exact version or it will break your EXE. There are some exceptions to this since RPG_RT of 2000-1.51 is same in 2000-1.52 and the patch for 2003-1.09 should work with every version above it (Maniac Patch for 2003-1.12 supported up to mp210414 only).
If you want to use this in combination with the patch
EXtraFONT, you have to apply that one first and afterwards, be sure to pick a "TextWidthEight96_" file from the list instead of just "TextWidthEight_" since it's optimized for use with EXtraFONT.